Some of the biggest black holes in the Universe may actually be even bigger than previously thought. This is according to a new survey of 18 of the largest known black holes using data from the Chandra X-ray Observatory and other telescopes. A group of astronomers studied black holes found in the centers of galaxy clusters that are filled with hot gas. They came up with the new estimates of the black hole masses by looking at the amount of X-rays and radio waves they generate. The researchers found that the black holes in the survey may be about ten times more massive than previously thought. This includes at least ten that could weigh between 10 and 40 billion times the mass of the sun, making them "ultramassive" black holes.
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Astronomers have found an extraordinary galaxy cluster -- one of the largest objects in the Universe -- that is breaking several important cosmic records. This galaxy cluster has been dubbed the "Phoenix Cluster" because not only is it located in the constellation of the Phoenix, it also possesses some remarkable properties of the mythological creature. While galaxies at the center of most clusters may have been dormant for billions of years, the central galaxy in this cluster seems to have come back to life with a new burst of star formation. The stars are forming at the highest rate ever observed for the middle of a galaxy cluster. Observations with NASA's Chandra X-ray Observatory, the NSF's South Pole Telescope and eight other world-class observatories were used to study this object. Taken together, the data from these telescopes also show the Phoenix Cluster is the most powerful producer of X-rays and among the most massive of galaxy clusters. It also has the highest rate of hot gas cooling in the central regions of a cluster ever observed. The new results from the Phoenix Cluster, which is located about 5.7 billion light years from Earth, may force astronomers to rethink how galaxy clusters, and the galaxies that inhabit them, evolve.
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This animation shows how large numbers of stars form in the Phoenix Cluster. It begins by showing several galaxies in the cluster and hot gas (in red). This hot gas contains more normal matter than all of the galaxies in the cluster combined, and can only be detected with X-ray telescopes like Chandra. The camera then flies in towards the large elliptical galaxy at the center of the cluster. The hot gas near this galaxy is giving off copious amounts of X-rays and cooling quickly over time, as shown by the change to a blue color. This cooling causes gas to flow inwards along filaments and form huge numbers of stars when it continues to cool.
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Using a combination of powerful observatories in space and on the ground, astronomers have discovered a violent collision between two galaxy clusters. During this collision, so-called normal matter has been wrenched apart from dark matter through a violent collision between two galaxy clusters. We see the normal matter in the form of hot gas thanks to X-rays detected by the Chandra X-ray Observatory. The location of the dark matter comes from optical data that reveal the effects of gravitational lensing, something Einstein predicted where large masses can distort the light from distant objects. The new galaxy cluster is called DLSCL J0916.2+2951. Rather than say that mouthful, researchers have nicknamed it the "Musket Ball Cluster." This name makes sense because this system is like an older and slower cousin to the famous Bullet Cluster. Finding another system that is further along in its evolution than the Bullet Cluster is very valuable. It gives scientists insight into a different phase of how galaxy clusters -- the largest known objects held together by gravity -- grow and change after major collisions.
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A galaxy cluster containing a structure never previously seen so far from Earth has been observed by NASA's Chandra X-ray Observatory. The cluster is also interesting to astronomers because a bright quasar, known as 3C 186, is found at its center. Dr. Aneta Siemiginowska of the Harvard-Smithsonian Center for Astrophysics led the team's research on this result and discusses it with us.
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Dark matter is mysterious. We know that it is invisible material that does not emit or absorb any type of light, but we can detect it through the gravitational effects it has on material we can see. Many scientists consider figuring out what dark matter is to be one of the biggest outstanding problems in astrophysics. Therefore, getting any new information about dark matter can help. Two teams of astronomers have used data from Chandra and other telescopes to map where the dark matter is in the galaxy cluster known as Abell 383. Not only were they able to find where dark matter lies in the two dimensions across the sky, they were also able to determine how the dark matter is distributed along the line of sight, or three dimensionally. So while there's still a long way to go before we know what dark matter is, results like these give astronomers important clues in this compelling cosmic mystery.
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This sequence of images shows "El Gordo" in X-ray light from NASA's Chandra X-ray Observatory, optical data from the European Southern Observatory's Very Large Telescope, and infrared emission from NASA's Spitzer Space Telescope, before revealing a composite of all of the wavelengths. Galaxy clusters are the largest objects in the universe that are held together by gravity, and can be used to study many things. Finding a galaxy cluster like El Gordo when the universe was less than half its current age helps astronomers better understand how the universe was evolving at that epoch.
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Astronomers using the Chandra X-ray Observatory and ground-based optical telescopes have discovered an extraordinary galaxy cluster some 7 billion light years from Earth. This cluster has been nicknamed "El Gordo," which means the "big" or "fat" one in Spanish. The nickname is a nod to the telescope in Chile that was used to help discover it, but also to the fact that El Gordo is the most massive, the hottest, and gives off more X-rays than any other galaxy cluster at this distance or beyond. The X-rays from Chandra and optical data from the VLT show that El Gordo is, in fact, the collision of two galaxy clusters ramming into one another at millions of miles per hour. This makes a younger cousin to the well-known Bullet Cluster. Galaxy clusters are very important for many reasons. As the largest objects in the Universe that are held together by gravity, galaxy clusters can be used to study the mysterious phenomena of dark matter and dark energy.
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The galaxy cluster Abell 2052 is found some 480 million light years from Earth. At the center of Abell 2052 is a giant elliptical galaxy, and within that is a supermassive black hole. X-ray data from Chandra show the hot gas that fills the space within the cluster. Pulling away, we see a huge spiral structure around this central elliptical galaxy. This spiral, which is over one million light years across, was created when a smaller spiral smashed into Abell 2052. This caused the hot gas in the cluster to slosh back and forth, similar to how wine moves when a glass is tugged from side to side. This sloshing turns out to be very important. First, it helps redistribute the hot gas, which, in turn, affects the number of new stars being formed in the central galaxy. The sloshing also spreads elements like oxygen and iron throughout the cluster, enriching future generations of stars and planets with the building blocks necessary for life as we know it.
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One of the most complicated and dramatic collisions ever seen between galaxy clusters is captured in this new composite image. This collision site, known officially as Abell 2744, has been dubbed "Pandora's Cluster" because of the wide variety of the different structures found here. Data from NASA's Chandra X-ray Observatory show gas with temperatures of millions of degrees. A map based on data from Hubble and two ground-based optical telescopes reveals the location of matter, most of which is the mysterious material known as dark matter. Working together, these telescopes show that Pandora's cluster is actually the result of the collision of at least four separate galaxy clusters, each coming from a different direction. Scientists think this cosmic smash-up has taken place over a span of some 350 million years.
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